Buick upstream front oxygen sensor 12634064 / 234-4565 / 12596688, GM quality assurance

When your Buick shows idle instability, obvious fuel consumption rise, check engine light on, or exhaust emissions exceed standards, it is likely the pre-cat oxygen sensor aging or failure. This sensor monitors oxygen content in exhaust in real time and feeds signals to the ECU to precisely control fuel injection, ensuring optimal air-fuel ratio. This general quality product has OEM number 12634064 and is compatible with models 234-4565, 12596688, 12590035, 12597449, 0258010260, etc., fitting Buick Excelle, Regal, LaCrosse, GL8, etc. Install only on a cold engine; carefully remove the old sensor to avoid damaging threads; use a dedicated socket and tighten to specified torque to prevent leaks.